def create_root_symbols(self):
"""Insert magical symbols above the root of the grammar in
order to match the beginning and end of the sample."""
RootSymbol = Symbol(Token(None,None,'R00t.Symbol'))
RootSymbol.GlobalSymbolDict=self.GlobalSymbolDict
StartDocSymbol = Symbol(Token(None,None,'%^'))
StartDocSymbol.regex = Set('%^')
StartDocSymbol.is_lit = True
StartDocSymbol.GlobalSymbolDict=self.GlobalSymbolDict
EndDocSymbol = Symbol(Token(None,None,'%$'))
EndDocSymbol.regex = Set('%$')
EndDocSymbol.is_lit = True
EndDocSymbol.GlobalSymbolDict=self.GlobalSymbolDict
RootSymbol.productions = [Production(RootSymbol,[StartDocSymbol]+self.get_roots()+[EndDocSymbol])]
self.GlobalSymbolDict['R00t.Symbol'] = RootSymbol #XXX this is a nasty hack
self.GlobalSymbolDict['%^']=StartDocSymbol
self.GlobalSymbolDict['%$']=EndDocSymbol
